Looking for name of old sci-fi book from the '70s or '80s that had main character with an aiming chip in his hand. His palm would itch and when he scratched it, it would make weird symbols appear in his vision.
At one point in the story he picked up some kind of revolver and the chip in his palm connected with the revolver and it seemed like time slowed and he was able to aim and mark enemies and fire the shots before anyone else moved. The chip made his reflexes super fast when used with the revolver.
I also believe later in the story there was some kind of fiery creature that would drop some kind of amber gems or something